Two-way ventilator

ABSTRACT

The ventilator is adapted for mounting in a vehicle cab and includes a swingable cover which may be opened in either a forward or rearward direction from a fully closed position. A slidable latch holds the cover releasably in its closed position, swings in unison with the cover when the latter is opened, and helps define the axes about which the cover swings.

United States Patent [191 Erickson Oct. 9, 1973 TWO-WAY VENTILATOR [75] Inventor: Gordon W. Erickson, Rockford, Ill.

[73] Assignee: Atwood Vacuum Machine Company, Rockford, Ill.

[22] Filed: Mar. 27, 1972 [21] Appl. No.: 238,092

[52] US. Cl 98/2, 98/2.l6, 98/2.18

[51] Int. Cl B60h 1/26 [58] Field of Search 98/2, 2.16, 2.17, 98/2.l8, 13, 18

[56] References Cited UNITED STATES PATENTS 3,672,291 6/1972 Kujawa 98/2.l6

1,654,715 1/1928 Affleck et a1. 98/2.16

2,159,516 5/1939 Ball 98/2.l6 x

2,070,113 2/19 37 Burgess 2,443,454 6/1948 Hennessy 3,046,865 7/1962 Kelly 3,102,464 9/1963 Kelly et a1 3,625,132 12/1971 Smith 98/2 18 Primary ExaminerWilliam F. ODea Assistant Examiner-Peter D. Ferguson Attorney-Wolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[5 7] ABSTRACT The ventilator is adapted for mounting in a vehicle cab and includes a swingable cover which may be opened in either a forward or rearward direction from a fully closed position. A slidable latch holds the cover releasably in its closed position, swings in unison with the cover when the latter is opened, and helps define the axes about which the cover swings.

Claims, 14 Drawing Figures EJBBJSO PATENTED 9 I975 SHEET 30F 4 1 Two-WAY VENTILATOR BACKGROUND OF THE INVENTION This invention relates to a ventilator for regulating the flow of air and, more particularly, to a two-way ventilator whose closure or cover is swingable in either of two directions from a closed position. Such a ventilator may be installed, for example, in the cab of a vehicle and positioned such that forward movement of the vehicle causes air to be blown into the cab when the cover is open in a forward direction and draws air from the cab when the cover is open in a rearward direction.

Ventilators of this general type are disclosed in U.S. Pat. Nos. 1,937,952 and 2,070,113. Morerecent examples of two-way ventilators are disclosed in U.S. Pat. Nos. 3,046,865 and 3,102,464.

SUMMARY OF THE INVENTION The general object of the present invention is to provide a ventilator of the above character which is of novel construction and which operates in a unique manner.

A more detailed object is to provide a ventilator with a unique latch for holding the cover tightly sealed when the latter is in the closed position and for helping confine the cover for swinging about either of two spaced axes when the cover is moved from the closed position.

These and other objects and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the outer side of a new and improved ventilator embodying the novel features of the present invention, the cover of the ventilator being shown in one open position.

FIG. 2 is an enlarged perspective view of the inner side of the ventilator illustrated in FIG. I, the cover being shown in a closed position.

FIGS. 3 and 4 are enlarged fragmentary crosssections taken substantially along the lines 3-3 and 4-4, respectively, of FIG. 2.

FIG. 5 is'a perspective view of one part of the ventilator.

FIG. 6 is an enlarged fragmentary cross-section taken substantially along the line 6-6 of FIG. 2.

FIGS. 7 and 8 are views similar to FIG. 6 but show successive steps which are undertaken to open the cover in one direction.

FIGS. 9 and 10 also are views similar to FIG. 6 but show successive steps which are undertaken to open the cover in the opposite direction.

FIG. 11 is a cross-sectional view similar to FIG. 6 but shows an alternative embodiment of a ventilator incorporating the features of the invention.

FIG. 12 is a fragmentary cross-section taken substantially along the line 12-12 of FIG. 11.

FIG. 13 is a cross-sectional view similar to FIG. 6 but illustrates still another embodiment of the invention, the cover being shown in a closed position.

FIG. 14 is a further cross-sectionalview of the ventilator illustrated in FIG. 13 and shows the cover in one open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings for purposes of illustration, the invention is embodied in an adjustable ventilator 15 which is particularly adapted for use in regulating the.

flow of air through the cab of a vehicle. The ventilator is shown here as installed in one side wall 16 of the cab of a truck and may be opened, closed or adjusted from the inside of the cab.

Specifically, the ventilator 15 includes a generally rectangular frame 17 positioned with its longer dimension extending vertically and formed with a peripheral flange 19 which is positioned against and riveted to the inner side of the side wall 16. Formed integrally with the flange and projecting outwardly through a rectangular hole 20 (FIG. 1) in the side wall is a lip 21 with a laterally extending rim 23 whose free edge defines the outer side of a rectangular opening 24 extending through the frame. Overall, the margins of the opening 24 through the frame are defined by the free edges and the inside surface of the rim 23, by the inboard surface of the lip 21 and by the inside surface of the flange 19.

To close the opening 24, a closure or cover 25 is supported on the outer side of the frame 17 and is formed with a peripheral skirt 26 which is adapted to telescope over the lip 21. A resiliently yieldable gasket 27 (FIG. 3) made of rubber or the like is carried on the inner side of the cover and seats against the rim 23 to form a weatherproof seal around the opening 24 when the cover is in its fully closed position shown in FIG. 6.

The cover 25 is adapted to be moved from the closed position and swung about either of the long margins of the opening 24 to either of two open positions shown in FIGS. 8 and 10. If the cover is swung outwardly about the forward margin of the opening and opened rearwardly to the position shown in FIG. 8, forward movement of the truck will cause any stale air in the cab to be drawn outwardly through the opening. When swung about the rear margin of the opening, the cover opens forwardly as shown in FIG. 10 so that forward movement of the truck will cause air to blow through the opening and into the cab. Accordingly, the ventilator 15 is of the two-way type in that the cover may be opened in either of two directions and swung to either of two oppositely inclined open positions.

In accordance with the present invention, provision is made on the cover 25 of uniquely constructed pivot mechanism 29 (FIG. 2) including a latch 30, the mechanism coacting in a novel manner with the margins of the opening 24 to hold the cover tightly in its closed position and, at the same time, to define the pivot axes of the cover and to constrain the cover for swinging about such axes between its closed and open positions. In addition, the pivot mechanism is capable of holding the cover securely but releasably in its fully open positions and in several intermediate positions located between its fully open and fully closed positions.

More particularly, one pivot mechanism 29 preferably is located at the upper end portion of the cover 25 while an identical mechanism is located at the lower end portion of the cover (see FIG. 2). Each mechanism comprises a generally triangular support plate 31 which is anchored rigidly to the inner side of the cover, projects inwardly through the opening 24, and carries the latch 30 of the mechanism. In this instance, the latch is in the form of a flat plate disposed faceto-face with the support plate 31 and located on the outboard side of the support plate.

As the cover 25 is swung outwardly from its closed position, both the latch 30 and the support plate 31 move in unison with the cover and swing partially through the opening 24 as shown in FIGS. 8 and 10. When the cover is in its closed position, however, the latch is slidable relative to the cover from a centered latched position (FIG. 6) to either of two released positions on opposite sides of the latched position (see FIGS. 7 and 9).

The latch 30 of the upper pivot mechanism 29 is adapted to be moved between its latched and released positions in unison with the latch of the lower pivot mechanism by manually pulling or pushing on a handle 33 (FIG. 2) positioned inwardly of the latches, the handle also serving to open or close the cover 25 upon being pushed or pulled when the latches are released. The handle is formed by the crosspiece of a U-shaped yoke whose legs constitute operating levers 34 which are operably connected to the latches and the cover. As shown in FIG. 3, each lever 34 is disposed face-to-face with the outboard side of the associated latch 30 and is mounted to pivot on the support plate 31 by means of a bolt 35 or other suitable pivot element. The bolt 35 is located intermediate the ends of the lever 34 and extends through a circular hole 36 in the lever, a large elongated slot 37 (FIG. 6) in the latch 30, and a slightly elongated slot 39 formed in the support plate 31 and extending transversely of the slot 37. A positive connection is established between the latch 30 and the free end portion of the lever 34 by a second pivot element in the form of a pin 40 (FIGS. 3 and 6) extending through the lever, the latch 30 and the support plate 31. Specifically, the pin extends through a slightly elongated slot 41 in the lever, is anchored rigidly in a circular hole 43 in the latch and extends through a large elongated slot 44 in the support plate. The large slot 44 in the support plate parallels the large slot 37 in the latch while the small slot 41 in the lever is elongated in the same direction as the small slot 39 in the support plate.

If the handle 33 is moved to turn the lever 34 clockwise from the position shown in FIG. 6, the lever pivots about the bolt 35 and acts through the pin 40 to slide the latch 30 from left to right from the latched position of FIG. 6 to the released position shown in FIG. 7. During such movement, the pin 40 travels in the elongated slot 44 in the support plate 31 while the elongated slot 37 in the latch accommodates movement of the latch past the bolt 35. When the lever is turned counterclockwise from the position shown in FIG. 6, the pin 40 shifts the latch from right to left and moves the latch to the released position shown in FIG. 9.

In carrying out the invention, elongated strips 46 (FIG. of resiliently yieldable metal are secured to the inner side of the flange 19 along the long margins of the opening 24 and are uniquely formed at their end portions to coact with the latch 30 and the support plate 31 for the purposes of holding the cover 25 closed and guiding the cover as the latter is swung open. Each strip 46 is anchored to the flange 19 by rivets 47 and includes an L-shaped section 49 fitting into the opening 24 and serving as a backing for a bug screen 50 (FIG. 2) whose long margins are sandwiched between one leg of the L and the inside face of the rim 23. Each end portion of each strip is formed with a cantilevered spring finger 51 (FIGS. 3 to 5) which projects laterally into the opening 24 and is adapted to flex horizontally toward and away from the adjacent margin of the opening. Just outboard of the finger 51, the end portion of each strip is formed with a cantilevered tab 53 whose free end portion is turned outwardly and projects laterally into overhanging relationship with the opening. By virtue of the resiliency of the strip, each tab is capable of flexing through a slight distance inwardly and outwardly of the opening and each is bent inwardly slightly relative to the plane of the strip so as to be loaded resiliently when pressed outwardly.

When the cover 25 is closed and the latch 30 is in its centered latched position shown in FIG. 6, the two tabs 53 at each end of the ventilator 15 are depressed by and bear inwardly against two outwardly facing shoulders 54 defined by the outer edges of cars 55 formed at opposite sides of the latch. The spacing between the inner surfaces of the tabs 53 and the outer face of the rim 23 is greater than the spacing between the shoulders 54 and the inner face of the gasket 27 when the latter is relaxed and thus, when the shoulders are in engagement with the tabs, the gasket is compressed tightly against the rim and the cover is held tightly closed. In addition, rounded surfaces on the spring fingers 51 bear against radiused surfaces on the edges of the support plate 31 as shown in FIG. 6 and bias the cover 25 inwardly to help keep the latter closed. Limited inward sliding of the latch 30 relative to the support plate 31 is permitted by virtue of the small slots 39 and 41 and thus, in the closed position of the cover, the aforementioned differential spacing causes the pin 40 to seat in a detent notch 57 located midway along the inner wall of the slot 44. Seating of the pin in the notch serves to positively hold the latch in its centered latched position.

To open the cover 25 rearwardly from the closed position shown in FIG. 6 to the open position shown in FIG. 8, the handle 33 is pushed or pulled to swing the levers 34 clockwise. During initial swinging of each lever, the pin 40 cams out of the detent notch 57 and travels along the slot 44 to move the latch 30 from left to right toward the released position shown in FIG. 7. As soon as the left shoulder 54 slides off of the left tab 53, continued left to right movement of the latch causes the latter to rock slightly in a clockwise direction relative to the support plate 31, the right tab and right shoulder serving as a fulcrum during such rocking.

As the latch is moved left to right, the cover 25 remains essentially stationary except that the left edge of the cover does spring outwardly through a slight distance when the left portion of the gasket relaxes upon release of the left shoulder 54 from the left tab 53.

Just shortly after the left shoulder 54 moves off of the left tab 53, an inclined surface 59 (FIG. 7) on the right edge of the latch engages the spring finger 51 to stop further left to right sliding of the latch and, at about the same time, the pin 40 bottoms against the right end of the slot 44. With continued clockwise swinging of the lever 34, the cover 25, the support plate 31 and the latch 30 all swing outwardly in unison thereby to open the cover rearwardly as shown in FIG. 8. During such swinging, the cover initially fulcrums about the corner between the lip 21 and the rim 23 while the latch 30 fulcrums about the right finger 51 and the right tab 53. The latter coacts with the right shoulder 54 to confine the cover for outward swinging and to prevent the cover from shifting bodily in and inward or outward direction. In addition, the left and right spring fingers 51 coact with the support plate 31 and the latch to prevent sliding of the latter and to confine the cover against lateral or edgewise movement. Thus, as the cover opens rearwardly, the left edge of the support plate 31 moves outwardly along and past the left finger 51 and thereafter the left edge of the latch 30 engages and rides along the left finger (see FIG. 8). Accordingly, the fingers prevent left-right sliding of the latch as the cover is opened and serve to captivate the cover against edgewise shifting.

Preferably, several notches 60 are formed in and spaced along each edge of the latch 30. Thus, the left finger 51 sequentially ratchets into and out of the notches on the left edge of the latch 30 as the cover 25 is opened rearwardly. If the cover is swung open only partially, the left finger will seat in the appropriate notch and will hold the cover releasably in the partially open position.

To close the cover 25 from its rearwardly opened position shown in FIG. 8, the handle 33 is pushed or pulled to swing each lever 34 in a counterclockwise direction. During the initial portion of such swinging, the lever, the latch 30 and the support plate 31 all pivot inwardly in unison with the cover and the latter fulcrums about the right portion of the rim 23 until the left portion of the gasket 27 engages the left portion of the rim to stop the cover in the position shown in FIG. 7. With continued swinging of the lever 34, the pin 40 slides the latch 30 from right to left to cause the left shoulder 54 of the latch to move toward the left tab 53. As the left shoulder first engages the left tab, the latter earns the latch in a counterclockwise direction (compare FIGS. 7 and 6) and causes the latch to draw the cover inwardly so as to compress the gasket into tight-sealing engagement with the rim 23. The left shoulder 54 then rides across the left tab 53 and holds the cover tightly closed as the lever reaches its centered position (see FIG. 6) and the pin 40 seats in the detent notch 57.

Opening of the cover 25 to its forwardly opened position is effected 'by following the same steps used to open the cover rearwardly but by swinging the lever 34 counterclockwise. Thus, the latch 30 first is moved right to left from its centered position shown in FIG. 6 to its released position shown in FIG. 9 and then the cover is swung outwardly about the left margin of the opening (see FIG. 10). During such swinging, the left tab 53 coacts with the left shoulder 54 and the left finger 51 coacts with the left inclined surface 59 of the latch to captivate the cover on the left margin of the opening 24. At the same time, the right finger 51 ratchets into and out of the notches 60 on the right edge of the latch to press the latter against the left finger and to releasably hold the cover in a given open position when swinging of the lever is terminated. In FIG. 10, the cover is shown fully open and, in this position, the extreme right inner corner of the latch engages the right tab 53 to prevent further outward swinging of the cover. Also, FIG. 10 shows that as the cover approaches its fully open position, the gasket 27 no longer pivots above the rim 23 but instead the fulcrum is established by engagement of the left portion of the skirt 26 with the adjacent portion of the lip 21. Accordingly, it will be appreciated that the true pivot axis of the cover changes or floats slightly as the cover is moved from its closed to its fully open position.

A modified ventilator 151 is shown in FIGS. 11 and 12 in which parts corresponding to those of the first embodiment are indicated by the same but primed reference numerals. In this instance, the lever 34' is disposed inboard of the latch 30' while the support plate 31' is located outboard of the latch. Also, the free end of the lever is not pinned directly to the latch but instead is disposed between two pins 40 which are anchored to the latch and extend through an elongated slot 44' in the support plate. Two detent notches 57' are formed in the inner wall of the slot on opposite sides of the lever and receive and hold the pins when the latch is in its centered latched position.

As shown in FIG. 11, opposite edges of the free end portion of the lever 34' are convexly radiused as indicated at and both radiused surfaces engage the pins 40' when the latch is disposed in its centered latched position. As the lever is turned about the bolt 35' to move the latch to either of its released positions, the pins rock on the radiused edges 75 to permit the latch to rock slightly as the appropriate shoulder 54' moves off of the adjacent tab 53'. After the pins have been forced out of the detent notches 57' and the latch has rocked through a short angular distance, the pins become captivated between the edges of the slot 44' and seats 76 defined at the junctions of the radiused edges 75 with the straight edges of the lever. As a result, the latch is prevented from rocking so far as to allow the outer edge of the latch to contact the inner side of the cover 25 and thus the cover will not become scored as the latch is repeatedly moved between its latched and unlatched positions during service use. In all other respects, the ventilator 15' functions the same as the ventilator 15 of the first embodiment and differs structurally therefrom only in the relative location of the latch 30', the supporting plate 31' and the lever 34' and in the nature of the connection between the lever and the latch.

Still another ventilator 15" is shown in FIGS. 13 and 14 and is structurally identical to the ventilator 15 of the first embodiment but for two exceptions. That is, in the ventilator 15", the edges of both the latch 30" and the support plate 31" are formed with generally the same curvature and, in addition, the detent notches 60" are formed on the edges of the support plate instead of on the edges of the latch.

As the cover 25 is swung, for example, to its rearwardly open position shown in FIG. 14, the notches 60" in the left edge of the support plate 30" ratchet past the left finger 51" and the latter holds the cover in a given open position by seating in one of the notches when clockwise swinging of the lever 34" is stopped. The left finger 51" also engages the left edge of the latch 30 each time the finger seats in one of the notches (see FIG. 14). Thus, when the lever is swung counterclockwise to close the cover from the position shown in FIG. 14, engagement of the left finger with the corresponding edge of the latch prevents the latch from being shifted from right to left and serves to captivate the latch until the cover is closed and the edge of the latch has moved inwardly past the finger. Thereafter, the latch may be moved from right to left and shifted to its latched position shown in FIG. 13.

I claim as my invention:

1. A ventilator comprising a frame having inner and outer sides and having an opening therethrough, a closure located on the outer side of said frame and swingable outwardly and inwardly about a first margin of the opening between a closed position and a first open position and about a second and opposite margin of the opening between said closed position and a second open position, mechanism projecting inwardly from and swingable with said closure and engageable with the margins of said opening to guide the closure for swinging between said closed and open positions and to hold the closure releasably in either of said open positions, said mechanism including a latch selectively positionable in a latched position in latching engagement with both margins of said opening to hold said closure in said closed position, and means mounting said latch for movement back and forth between the margins of the opening and relative to said closure from said latched position to:

a. a first released position in which said latch is disposed out of latching engagement with the second margin of said opening to permit swinging of said closure about said first margin to said first open position, and

b. a second released position in which said latch is disposed out of latching engagement with the first margin of the opening to permit swinging of said closure about said second margin to said second open position.

2. A ventilator as defined in claim 1 in which said latch is mounted on said closure to swing in unison with the closure as the latter is swung between said closed and open positions and also is mounted to shift on the closure and toward and away from said margins upon being moved between said latched and released positions, said latch comprising a plate having first and second outwardly facing shoulders located adjacent the respective margins and both disposed in latching engagement with the inner side of said frame when the latch is in said latched position.

3. A ventilator as defined in claim 2 in which said first shoulder remains in latching engagement with the inner side of said frame and said second shoulder shifts out of latching engagement with the inner side of the frame when said latch is moved from said latched position to said first released position, said second shoulder remaining in latching engagement with the inner side of the frame and said first shoulder shifting out of latching engagement with the inner side of the frame when said latch is moved from said latched position to said second released position.

4. A ventilator as defined in claim 3 further including tabs mounted on the inner side of said frame adjacent said margins and engaging said shoulders when said latch is in said latched position thereby to hold said closure inwardly against the outer side of said frame.

5. A ventilator as defined in claim 4 further including a rim extending around the outer side of said frame, a resiliently compressible gasket extending around the inner side of said closure and engageable with said rim when said closure is in said closed position, the spacing between the inner surfaces of said tabs and the outer surface of said rim being greater than the spacing between said shoulders and the inner surface of said gasket when the latter is relaxed.

6. A ventilator as defined in claim 2 in which first and second series of spaced notches are formed in the respective edges of said latch plate, and further including springs projecting toward said opening from each of said margins and biased into engagement with the opposite edges of said latch plate, the spring projecting from said first margin seating sequentially in the notches of said first series as said closure is swung toward said second open position, and the spring projecting from said second margin seating sequentially in the notches of said second series as said closure is swung toward said first open position.

7. A ventilator as defined in claim 1 further including springs projecting toward said opening from each of said margins and biased into engagement with said mechanism to hold said closure releasably in said first and second open positions.

8. A ventilator as defined in claim 7 in which said springs comprise resiliently yieldable metal strips cantilevered on said frame and biased to project into said opening.

9. A ventilator as defined in claim 1 further including a member anchored rigidly to the inner side of said closure and projecting inwardly through said opening, and an operating lever connected intermediate its ends to pivot on said member and connected at its outer end to said latch to shift the latter back and forth between said positions.

10. A ventilator as defined in claim 9 in which said member, said latch and said lever are disposed side-byside, an inner pivot element connecting the lever pivotally on said member, at least one outer pivot element extending through the member and the latch and connecting the outer end of the lever pivotally to the latch, and a substantially straight elongated slot formed in said member and guiding said outer pivot element for sliding toward and away from said margins in response to swinging of said lever about said inner pivot element.

11. A ventilator as defined in claim 10 in which said inner pivot element extends through said member, said latch and said lever, and an elongated slot formed in said latch and receiving said inner pivot element to enable shifting of said latch.

12. A ventilator as defined in claim 9 in which first and second series of spaced notches are formed on opposite edges of said member, and further including springs projecting toward said opening from each of said margins and biased into engagement with the opposite edges of said member, the spring projecting from said first margin seating sequentially in the nothces of said first series as said closure is swung toward said second open position, and the spring projecting from said second margin seating sequentially in the notches of said second series as said closure is swung toward said first open position.

13. A ventilator comprising a frame having inner and outer sides and having an opening therethrough, a closure located on the outer side of said frame and swingable outwardly and inwardly about a first margin of the opening between a closed position and a first open position and about a second and opposite margin of the opening between said closed position and a second open position, mechanism projecting inwardly from and swingable with said closure and engageable with the margins of said opening to guide the closure for swinging between said closed and open positions and to hold the closure releasably in each of said positions, and said mechanism including a latch mounted for movement back and forth between the margins of the opening and relative to said closure between:

a. a first position latching against said first margin and disposed out of latching engagement with said second margin to permit swinging of said closure about the first margin from said closed position to.

said first open position, and

b. a second position latching against said second margin and disposed out of latching engagement with said first margin to permit swinging of said closure about the second margin from said closed position to said second open position.

14. A ventilator comprising a frame having inner and outer sides and having an opening therethrough, a closure located on the outer side of said frame and swingable outwardly and inwardly about a first margin of the opening between a closed position and a first open position and about a second and opposite margin of the opening between said closed position and a second open position, first and second tabs of resiliently yieldable material cantilevered on the inner side of said frame and adjacent the respective margins, a latching plate mounted to swing with said closure as the latter is moved between its positions and also mounted to move relative to the closure between a latched position and first and second released positions on opposite sides of said latched position, said latching plate including first and second outwardly facing shoulders which engage the respective tabs when said plate is in said latched position and hold said closure in said closed position against the outer side of said frame, one of said shoulders being released from its associated tab and the other shoulder remaining engaged with its associated tab when said latch is in one of said released positions whereby the released shoulder permits swinging of said closure to one of said open positions while the engaged shoulder helps confine the closure for swinging about the corresponding margin, first and second fingers of resiliently yieldable material cantilevered on said frame adjacent the respective margins and each positioned for lateral flexure toward the adjacent margin, said fingers engaging the edges of said latching plate during swinging of said closure between its positions thereby to help confine the closure for swinging about said margins.

15. A ventilator as defined in claim 14 further including a support plate anchored rigidly to and projecting,

inwardly from said closure and mounting said latching plate for swinging with said closure and also for movement relative to said closure, said fingers engaging the adjacent edges of said support plate when said latching plate is in said latched position and said closure is in said closed position.

16. A ventilator as defined in claim 15 in which one of said fingers remains in engagement with the adjacent edge of said support plate and the other finger engages the adjacent edge of said latching plate when said closure is in one of said open positions.

17. A ventilator as defined in claim 16 in which notches are formed in and spaced along the edges of one of said plates and sequentially receive said fingers during swinging of said closure.

18. A ventilator as defined in claim 17 in which said notches are formed in the edges of said latching plate.

19. A ventilator as defined in claim 17 in which said notches are formed in the edges of said support plate. t 

1. A ventilator comprising a frame having inner and outer sides and having an opening therethrough, a closure located on the outer side of said frame and swingable outwardly and inwardly about a first margin of the opening between a closed position and a first open position and about a second and opposite margin of the opening between said closed position and a second open position, mechanism projecting inwardly from and swingable with said closure and engageable with the margins of said opening to guide the closure for swinging between said closed and open positions and to hold the closure releasably in either of said open positions, said mechanism including a latch selectively positionable in a latched position in latching engagement with both margins of said opening to hold said closure in said closed position, and means mounting said latch for movement back and forth between the margins of the opening and relative to said closure from said latched position to: a. a first released position in which said latch is disposed out of latching engagement with the second margin of said opening to permit swinging of said closure about said first margin to said first open position, and b. a second released position in which said latch is disposed out of latching engagement with the first margin of the opening to permit swinging of said closure about said second margin to said second open position.
 2. A ventilator as defined in claim 1 in which said latch is mounted on said closure to swing in unison with the closure as the latter is swung between said closed and open positions and also is mounted to shift on the closure and toward and away from said margins upon being moved between said latched and released positions, said latch comprising a plate having first and second outwardly facing shoulders located adjacent the respective margins and both disposed in latching engagement with the inner side of said frame when the latch is in said latched position.
 3. A ventilator as defined in claim 2 in which said first shoulder remains in latching engagement with the inner side of said frame and said second shoulder shifts out of latching engageMent with the inner side of the frame when said latch is moved from said latched position to said first released position, said second shoulder remaining in latching engagement with the inner side of the frame and said first shoulder shifting out of latching engagement with the inner side of the frame when said latch is moved from said latched position to said second released position.
 4. A ventilator as defined in claim 3 further including tabs mounted on the inner side of said frame adjacent said margins and engaging said shoulders when said latch is in said latched position thereby to hold said closure inwardly against the outer side of said frame.
 5. A ventilator as defined in claim 4 further including a rim extending around the outer side of said frame, a resiliently compressible gasket extending around the inner side of said closure and engageable with said rim when said closure is in said closed position, the spacing between the inner surfaces of said tabs and the outer surface of said rim being greater than the spacing between said shoulders and the inner surface of said gasket when the latter is relaxed.
 6. A ventilator as defined in claim 2 in which first and second series of spaced notches are formed in the respective edges of said latch plate, and further including springs projecting toward said opening from each of said margins and biased into engagement with the opposite edges of said latch plate, the spring projecting from said first margin seating sequentially in the notches of said first series as said closure is swung toward said second open position, and the spring projecting from said second margin seating sequentially in the notches of said second series as said closure is swung toward said first open position.
 7. A ventilator as defined in claim 1 further including springs projecting toward said opening from each of said margins and biased into engagement with said mechanism to hold said closure releasably in said first and second open positions.
 8. A ventilator as defined in claim 7 in which said springs comprise resiliently yieldable metal strips cantilevered on said frame and biased to project into said opening.
 9. A ventilator as defined in claim 1 further including a member anchored rigidly to the inner side of said closure and projecting inwardly through said opening, and an operating lever connected intermediate its ends to pivot on said member and connected at its outer end to said latch to shift the latter back and forth between said positions.
 10. A ventilator as defined in claim 9 in which said member, said latch and said lever are disposed side-by-side, an inner pivot element connecting the lever pivotally on said member, at least one outer pivot element extending through the member and the latch and connecting the outer end of the lever pivotally to the latch, and a substantially straight elongated slot formed in said member and guiding said outer pivot element for sliding toward and away from said margins in response to swinging of said lever about said inner pivot element.
 11. A ventilator as defined in claim 10 in which said inner pivot element extends through said member, said latch and said lever, and an elongated slot formed in said latch and receiving said inner pivot element to enable shifting of said latch.
 12. A ventilator as defined in claim 9 in which first and second series of spaced notches are formed on opposite edges of said member, and further including springs projecting toward said opening from each of said margins and biased into engagement with the opposite edges of said member, the spring projecting from said first margin seating sequentially in the nothces of said first series as said closure is swung toward said second open position, and the spring projecting from said second margin seating sequentially in the notches of said second series as said closure is swung toward said first open position.
 13. A ventilator comprising a frame having inner and outer sides and having an openinG therethrough, a closure located on the outer side of said frame and swingable outwardly and inwardly about a first margin of the opening between a closed position and a first open position and about a second and opposite margin of the opening between said closed position and a second open position, mechanism projecting inwardly from and swingable with said closure and engageable with the margins of said opening to guide the closure for swinging between said closed and open positions and to hold the closure releasably in each of said positions, and said mechanism including a latch mounted for movement back and forth between the margins of the opening and relative to said closure between: a. a first position latching against said first margin and disposed out of latching engagement with said second margin to permit swinging of said closure about the first margin from said closed position to said first open position, and b. a second position latching against said second margin and disposed out of latching engagement with said first margin to permit swinging of said closure about the second margin from said closed position to said second open position.
 14. A ventilator comprising a frame having inner and outer sides and having an opening therethrough, a closure located on the outer side of said frame and swingable outwardly and inwardly about a first margin of the opening between a closed position and a first open position and about a second and opposite margin of the opening between said closed position and a second open position, first and second tabs of resiliently yieldable material cantilevered on the inner side of said frame and adjacent the respective margins, a latching plate mounted to swing with said closure as the latter is moved between its positions and also mounted to move relative to the closure between a latched position and first and second released positions on opposite sides of said latched position, said latching plate including first and second outwardly facing shoulders which engage the respective tabs when said plate is in said latched position and hold said closure in said closed position against the outer side of said frame, one of said shoulders being released from its associated tab and the other shoulder remaining engaged with its associated tab when said latch is in one of said released positions whereby the released shoulder permits swinging of said closure to one of said open positions while the engaged shoulder helps confine the closure for swinging about the corresponding margin, first and second fingers of resiliently yieldable material cantilevered on said frame adjacent the respective margins and each positioned for lateral flexure toward the adjacent margin, said fingers engaging the edges of said latching plate during swinging of said closure between its positions thereby to help confine the closure for swinging about said margins.
 15. A ventilator as defined in claim 14 further including a support plate anchored rigidly to and projecting inwardly from said closure and mounting said latching plate for swinging with said closure and also for movement relative to said closure, said fingers engaging the adjacent edges of said support plate when said latching plate is in said latched position and said closure is in said closed position.
 16. A ventilator as defined in claim 15 in which one of said fingers remains in engagement with the adjacent edge of said support plate and the other finger engages the adjacent edge of said latching plate when said closure is in one of said open positions.
 17. A ventilator as defined in claim 16 in which notches are formed in and spaced along the edges of one of said plates and sequentially receive said fingers during swinging of said closure.
 18. A ventilator as defined in claim 17 in which said notches are formed in the edges of said latching plate.
 19. A ventilator as defined in claim 17 in which said notches are formed in the edges of said support plate. 